031  
FXUS65 KBYZ 130932  
AFDBYZ  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE BILLINGS MT  
332 AM MDT SAT APR 13 2024  
   
DISCUSSION
 
 
TODAY THROUGH SUNDAY NIGHT...  
 
ANOTHER WARM DAY CAN BE EXPECTED ACROSS THE AREA TODAY AS HEIGHTS  
BUILD IN FROM THE SOUTH AND WEST. MOISTURE AND ENERGY WILL ADVECT  
INTO WESTERN AND CENTRAL PORTIONS OF THE AREA THIS AFTERNOON AND  
EVENING, ASSOCIATED WITH AN UPPER LOW ALONG THE CALIFORNIA COAST.  
THIS WILL BRING ISOLATED TO WIDELY SCATTERED SHOWERS AND  
THUNDERSTORMS (30% CHANCE OR LESS) LATER THIS AFTERNOON AND  
EVENING. BRIEF HEAVY RAIN AND GUSTY WINDS ARE POSSIBLE WITH THE  
STRONGER SHOWERS/THUNDERSTORMS. AT THE SAME TIME, A WEAK FRONTAL  
BOUNDARY WILL DROP INTO THE AREA FROM THE NORTH THIS AFTERNOON  
TURNING WINDS OUT OF THE NORTH. RH WILL BE A BIT HIGHER ACROSS THE  
NORTH, BUT TEMPERATURES WILL STILL BE WITHIN A FEW DEGREES OF  
YESTERDAY'S TEMPERATURES. TEMPERATURES WILL APPROACH RECORDS AT  
ALL CLIMATE SITES, REACHING THE 70S TO AROUND 80 DEGREES.  
 
HEADING INTO SUNDAY, THE AFOREMENTIONED UPPER LOW WILL MOVE  
INLAND OVER CALIFORNIA/NEVADA, AND THE RIDGE AXIS OVER THE  
NORTHERN ROCKIES WILL SHIFT EAST OVER EASTERN MONTANA. ISOLATED TO  
SCATTERED SHOWERS AND THUNDERSTORMS (30% CHANCE OR LESS) WILL  
ONCE AGAIN DEVELOP OVER THE MOUNTAINS IN THE AFTERNOON, MOVING OUT  
ONTO THE ADJACENT PLAINS THROUGH THE EVENING. TEMPERATURES ON  
SUNDAY ARE FORECAST TO REACH THE UPPER 70S TO LOWER 80S, WARMEST  
OVER EASTERN AREAS. RECORD HIGH TEMPERATURES ARE POSSIBLE ONCE  
AGAIN AT ALL CLIMATE SITES. STP  
 
MONDAY THROUGH SATURDAY...  
 
THE SIGNAL FOR COOLER AND WETTER WEATHER CONTINUES FOR NEXT WEEK,  
BUT UNCERTAINTY STILL REMAINS IN THE ENSEMBLE FORECASTS THIS  
MORNING. AT THIS TIME, THE BEST PRECIPITATION POTENTIAL RESIDES IN  
FAR SOUTHEASTERN MT MONDAY EVENING INTO TUESDAY MORNING AND ALONG  
THE FOOTHILLS AND MOUNTAINS OF SOUTH CENTRAL MT TUESDAY EVENING  
THROUGH WEDNESDAY. TEMPERATURES HAVE ALSO TRENDED SLIGHTLY WARMER  
FOR THE EVENT OVER THE LAST 24 HOURS.  
 
MONDAY WILL BE A WARM DAY ACROSS THE AREA WITH HIGHS IN THE 60S  
TO LOWER 70S (DEGF). DURING THIS TIME, WE WILL BE UNDER SPLIT FLOW  
WITH THE DEVELOPING TROUGH TO THE NW AND CUT-OFF UPPER LOW TO OUR  
SOUTH. THE LOW TO OUR SOUTH WILL TRACK CLOSE ENOUGH TO BRING  
INCREASED PRECIPITATION CHANCES (40-60%) TO SOUTH CENTRAL AND  
EASTERN MT AND NORTHERN WY DURING THE AFTERNOON THROUGH OVERNIGHT  
HOURS MONDAY INTO TUESDAY. IN FAR SOUTHEASTERN MT, GULF MOISTURE  
WRAPPING AROUND THE LOW, COMBINED WITH DECENT INSTABILITY (400-600  
J/KG OF CAPE), WILL ALLOW FOR THE POTENTIAL FOR THUNDERSTORMS, AS  
WELL AS HEAVY RAIN, DURING THIS TIME.  
 
AS THE AFOREMENTIONED LOW MOVES EAST TUESDAY MORNING, CHANCES FOR  
PRECIPITATION WILL DECREASE. BY TUESDAY AFTERNOON AND EVENING,  
THE TROUGH TO THE NW LOOKS TO DROP INTO MONTANA, REINTRODUCING  
PRECIPITATION CHANCES TO THE REGION (30-80%, HIGHEST OVER THE  
FOOTHILLS AND MOUNTAINS AND LOWEST FROM MILES CITY TO BAKER). THE  
WESTERN AND SOUTHERN EXTENT OF THE TROUGH IS WHERE THE UNCERTAIN  
REMAINS IN THE ENSEMBLE FORECASTS. THE GEFS INTRODUCES LOWER  
HEIGHTS INTO WESTERN AND SOUTHERN MT WHICH ALLOWS FOR DEEPER  
UPSLOPE FLOW AND ASSOCIATED HEAVIER PRECIPITATION TO OCCUR TUESDAY  
EVENING THROUGH WEDNESDAY ALONG THE FOOTHILLS AND MOUNTAINS OF  
SOUTH CENTRAL MT. THE ECMWF AND CANADIAN ENSEMBLES KEEP THE LOWER  
HEIGHTS IN NORTHEASTERN MT, LIMITING THE UPSLOPE FLOW AND  
ASSOCIATED PRECIPITATION ACROSS THE AREA. THIS WILL BE THE FACTOR  
TO WATCH GOING FORWARD. RIGHT NOW, THE CHANCE FOR A HALF INCH OR  
MORE OF LIQUID MONDAY THROUGH THURSDAY MORNING IS 40-70% IN FAR  
SOUTHEAST MT AND 50-80% OVER THE FOOTHILLS AND MOUNTAINS.  
 
TEMPERATURES HAVE ALSO WARMED SLIGHTLY OVER THE PAST 24 HOURS FOR  
TUESDAY THROUGH THURSDAY WITH HIGHS IN THE UPPER 50S TO LOWER 60S  
TUESDAY AND LOWER TO UPPER 40S FOR MOST WEDNESDAY AND THURSDAY.  
THIS WILL LIMIT THE POTENTIAL SNOW IMPACTS OVER THE LOWER  
ELEVATIONS. BREEZY CONDITIONS WILL ALSO DEVELOP TUESDAY THROUGH  
THURSDAY, WITH THE STRONGEST WINDS EXPECTED OVER FAR EASTERN MT  
(WIND GUSTS IN THE 20 TO 45 MPH RANGE, STRONGEST WEDNESDAY).  
ARENDS  
 

 
   
AVIATION
 
 
RAIN SHOWERS WEST OF KBIL WILL TAPER OFF EARLY THIS MORNING,  
ALLOWING VFR CONDITIONS TO PREVAIL AT ALL TAF SITES TODAY. THIS  
AFTERNOON AND EVENING, ISOLATED TO SCATTERED SHOWERS AND A WEAK  
THUNDERSTORM OR TWO ARE EXPECTED TO DEVELOP ONCE AGAIN,  
POTENTIALLY IMPACTING KLVM, KBIL, AND KSHR. AS FAR AS WINDS GO,  
EXPECT WINDS TO SHIFT OUT OF THE NW MID-DAY TODAY. ARENDS  
 

 
   
PRELIMINARY POINT TEMP/POPS
 
 
TDY SUN MON TUE WED THU FRI  
-------------------------------------------------------  
BIL 077 044/079 048/071 046/062 037/044 032/047 030/051  
2/T 21/U 24/R 33/R 46/O 34/O 22/O  
LVM 077 043/078 044/065 040/057 034/042 028/046 027/049  
2/T 22/T 24/R 24/R 65/O 33/O 11/B  
HDN 077 043/080 045/074 046/064 035/045 030/049 028/053  
1/U 21/U 24/R 32/R 46/O 44/O 22/S  
MLS 076 044/082 046/073 048/061 035/045 030/045 028/049  
0/U 00/U 11/B 21/N 23/O 33/S 21/B  
4BQ 078 044/083 046/073 047/061 035/045 029/045 027/047  
0/U 00/U 01/B 42/R 23/O 33/S 21/B  
BHK 078 041/081 044/072 044/061 032/043 026/042 024/045  
0/U 01/U 11/B 43/R 23/O 33/S 21/B  
SHR 078 042/078 043/068 043/060 033/041 027/043 024/048  
1/U 10/U 13/R 43/R 56/O 43/S 22/O  
 

 
   
BYZ WATCHES/WARNINGS/ADVISORIES
 
 
MT...NONE.  
WY...NONE.  
 

 
 

 
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